MC68181 Datasheet, PDF (75/119 Pages) Freescale Semiconductor, Inc – Advance Information ROAMING FLEX chip SIGNAL PROCESSOR

Freescale Semiconductor, Inc.
MC68181
Host-to-Decoder Packet Descriptions
Roaming Control Packet
The Roaming Control Packet controls the features of the Roaming FLEX chip IC that
allow implementation of a roaming device. The ID of the roaming control packet is 5.
Byte
3
2
1
0
Table 1: Roaming Control Packet Bit Assignments
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1
0
0
0
0
0
IRS
NBC MCM
IS1
SDF
RND
ABI
SAS
DAS
0
0
0
MFC₁ MFC₀
0
1
0
RSP
SND
0
0
0
MCO₁
Bit 0
1
CND
0
MCO₀
IGNORE RE-SYNCHRONIZATION SIGNAL (IRS)
When this bit is set, the FLEX chip will not go asynchronous when detecting an Ar or
Ar signal during searches for A-words. It will merely report that the re-
synchronization signal was received by setting RSR to 1 in the Roaming Status
packet. This allows the host to decide what to do when the paging device is
synchronous to more than one channel and only one channel is sending the re-
synchronization signal. It also prevents the FLEX chip from losing synchronization
when it detects the re-synchronization signal while the paging device is checking an
unknown channel. This bit is set and cleared by the host. The value after reset = 0.
NETWORK BIT CHECK (NBC)
Setting this bit will enable reporting of the received network bit value (NBU and n) in
the Roaming Status Packet. Setting this bit also makes the FLEX chip abandon a frame
after the Frame Info word without synchronizing to the frame if the frame
information word is uncorrectable or if the n bit in the frame information word is not
set. If the FLEX chip IC was in synchronous mode when this occurred (probably due
to synchronizing to a second channel), it will maintain synchronization to the original
channel. If the FLEX chip IC was in asynchronous mode when this occurred, it will
stay in asynchronous mode and end the A-word search. This is done to avoid
synchronizing to a non-roaming channel when searching for roaming channels. This
bit is set and cleared by the host. The value after reset = 0.
MANUAL COLLAPSE MODE (MCM)
When this bit is set, the FLEX chip behaves as if the system collapse was 7. FLEX chip
will not apply the received system collapse to the AF bits. When this bit is set, the
received system collapse is reported to the host via SCU and RSC in the Roaming
Status Packet. This is so the host can modify the AF bits based on the system collapse
of the channel. This bit is set and cleared by the host. (value after reset = 0)
MOTOROLA
MC68181 Technical Data Sheet
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